Add unit tests for cases that `mul_op` takes tensors as inputs
Add unit tests for cases that `mul_op` takes tensors as inputs

pengli09/Paddle,PaddlePaddle/Paddle,luotao1/Paddle,pengli09/Paddle,luotao1/Paddle,hedaoyuan/Paddle,tensor-tang/Paddle,pkuyym/Paddle,pengli09/Paddle,tensor-tang/Paddle,reyoung/Paddle,reyoung/Paddle,jacquesqiao/Paddle,pkuyym/Paddle,putcn/Paddle,putcn/Paddle,PaddlePaddle/Paddle,jacquesqiao/Paddle,luotao1/Paddle,PaddlePaddle/Paddle,luotao1/Paddle,pkuyym/Paddle,PaddlePaddle/Paddle,baidu/Paddle,QiJune/Paddle,chengduoZH/Paddle,Canpio/Paddle,baidu/Paddle,baidu/Paddle,tensor-tang/Paddle,luotao1/Paddle,putcn/Paddle,jacquesqiao/Paddle,baidu/Paddle,tensor-tang/Paddle,Canpio/Paddle,QiJune/Paddle,putcn/Paddle,putcn/Paddle,pkuyym/Paddle,luotao1/Paddle,pengli09/Paddle,baidu/Paddle,putcn/Paddle,lcy-seso/Paddle,Canpio/Paddle,jacquesqiao/Paddle,pkuyym/Paddle,reyoung/Paddle,Canpio/Paddle,hedaoyuan/Paddle,QiJune/Paddle,reyoung/Paddle,chengduoZH/Paddle,QiJune/Paddle,hedaoyuan/Paddle,jacquesqiao/Paddle,Canpio/Paddle,pengli09/Paddle,reyoung/Paddle,pengli09/Paddle,jacquesqiao/Paddle,chengduoZH/Paddle,pengli09/Paddle,pengli09/Paddle,Canpio/Paddle,tensor-tang/Paddle,lcy-seso/Paddle,hedaoyuan/Paddle,pkuyym/Paddle,lcy-seso/Paddle,lcy-seso/Paddle,QiJune/Paddle,Canpio/Paddle,lcy-seso/Paddle,PaddlePaddle/Paddle,hedaoyuan/Paddle,Canpio/Paddle,hedaoyuan/Paddle,chengduoZH/Paddle,luotao1/Paddle,chengduoZH/Paddle,PaddlePaddle/Paddle,PaddlePaddle/Paddle,QiJune/Paddle,hedaoyuan/Paddle,lcy-seso/Paddle,hedaoyuan/Paddle,reyoung/Paddle